Movable audio/video communication interface system

ABSTRACT

A system that includes a desk top assembly of a display and sensors mounted on a robotic arm. The arm moves the assembly so that it remains within position and orientation tolerances relative to the user&#39;s head as the user looks around. Near-field speaker arrays supply audio and a microphone array senses a user&#39;s voice. Filters are applied to head motion to reduce latency for arm&#39;s tracking of the head. The system is full duplex with other systems allowing immersive collaboration. Lighting and sound generation take place close to the user&#39;s head. A haptic interface device allows the user to grab the display/sensor array and move it about. Motion acts as a planar selection device for 3D data. Planar force feedback allows a user to “feel” the data. Users see not only each other through display windows, but can also see the positions and orientations of each others&#39; planar selections of shared 3D models or data.

CROSS-REFERENCE TO RELATED APPLICATION

This application is related to and claims priority to U.S. provisionalapplication entitled A Movable Audio Video Communication InterfaceSystem having Ser. No. 60/621,085, by Lanier, filed Oct. 25, 2004 andincorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to a system for immersing a user intoa multi-dimensional collaborative environment using position tracking toadjust a position of a display displaying a 3D scene and/or otherparticipants in the collaboration.

2. Description of the Related Art

In the past a number of different technologies have been used to helppeople collaborate at a distance by coupling them together in some sortof common environment. These technologies have includes conferencetelephone systems, video telephones, networked head mounted displays,collaborative document software, etc. These technologies suffer from aninability to create a viable personal communications and computingenvironment for collaboration among individuals in part because theunderlying sensor and display components are not used in a way thatallows them to perform well enough to meet human factors needs. What isneeded is a better such system.

For instance, video conferencing systems cannot provide true sight linesbetween participants, because the camera and display are in differentpositions. Therefore eye contact between participants is impossible.This problem has led to a very large number of attempted solutions overa period of three quarters of a century.

One class of solutions is to reduce the effects of imperfect sight linesby the use of other design elements, while another is to find ways togenerate accurate sight lines. Accurate sight lines require dynamictracking of the positions of the eyes of users, and generally requirethat the visual scene presented to each eye be digitally reconstructedto be of the correct perspective, since it is difficult to consistentlyplace a physical camera at the correct position to capture the properperspective. This approach is generally called tele-immersion. Atele-immersion example is Jaron Lanier's prototype described in theScientific American article referenced. Several problems have madetele-immersion systems impractical. One is that displays andeye-position sensors that are currently available or are foreseen to beavailable in the near future do not work well outside of narrowtolerances for the position and orientation of the user's head. Forinstance, in order for participants to be able to be apparently placedclose to each other in a shared virtual space, stereo vision must besupported, but for each eye to see a unique point of view, either someform of eyeware must be worn, or an autostereo display must be used, butavailable autostereo displays place restrictions on a user's headposition. Because of these problems, it has been difficult to designtele-immersion systems that combine true sight lines, full duplex(meaning that users can see each other without problems due tointervening machinery such as stereo viewing glasses), and flexiblevirtual placement (meaning that viewers can be placed at any distance,near or far, and in any arrangement.) Another problem has been thattele-immersion systems have generally required dedicated rooms, whichhas limited their practicality. The physical layout of tele-immersioninstrumentation has placed restrictions on the virtual layout ofparticipants in the virtual space. The blue-c system generates truesight lines but places restrictions on relative placements of users invirtual space, cannot support high resolution sensing or display withcurrently available components, and requires dedicated rooms. The HPColiseum system cannot support true sight lines and generalizedplacement of participants at the same time.

SUMMARY OF THE INVENTION

It is an aspect of the present invention to provide a personalcommunications and computing environment that can also be used forcollaboration among individuals.

It is another aspect of the present invention to provide an immersivetype collaboration experience.

It is also an aspect of the present invention to provide an immersivetype experience that can be easily integrated with other modes ofworking.

It is also an aspect of the present invention to provide an immersivetype of experience without requiring large resources of floor space orspecialized rooms.

The above aspects can be attained by a system that includes an assemblyof multimodal displays and sensors mounted on a mechanical or roboticarm rising out of a desktop or other base. The arm moves the assembly sothat it remains within position and orientation tolerances relative tothe user's head as the user looks around. This lowers the requirementsfor sensor and display components so that existing sensors and displayscan work well enough for the purpose. The arm does not need to be movedwith great accuracy or maintain perfect on-axis alignment and uniformdistance to the face. It must merely remain within tolerances. Kalmanfilters are applied to head motion to compensate for latency in thearm's tracking of the head. Tele-immersion is supported by the assemblybecause local and remote user's heads can be sensed and then representedto each other with true sight lines. By placing user interfacetransducers in motion, it becomes possible for users to move as theynormally would in group interactions, particularly those including morethan two participants. The invention provides a solution that is fullduplex and yet has a small footprint. Users can be placed in anyarrangement in virtual space. Because lighting and sound generation takeplace close to the user's head, the invention will not disrupt otheractivities in the local physical environment. Near-field speaker arrayssupply immersive audio and a microphone array senses a users voice. Inthis way a user can be alerted by an audio event such as a voice to lookin the direction of the event. Since the display will move to show whatis present in that direction, the display need not be encompassing, orrestrict access to the local physical environment, in order for the userto benefit from immersive virtual environments. The invention is also ahaptic interface device; a user can grab the display/sensor array andmove it about. The invention acts as a planar selection device for 3Ddata. This is important for volumetric data, such as MRI scan data. Thephysical position and orientation of display assembly provides planarselection and the need for mental rotation is reduced. Planar forcefeedback can also be used to allow a user to feel the center of densitywithin a scalar field as resistance and curl. Users see not only eachother through display windows, but can also see the positions andorientations of each others' planar selections of shared 3D models ordata, so area of interest is communicated with minimal effort. Theinvention can also be used to subsume or simulate other user interfacedesigns, such as command control rooms with multiple displays,wall-sized displays, “videobots,” or conventional desktop PC displays.

These together with other aspects and advantages which will besubsequently apparent, reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the components of a system according to the presentinvention.

FIG. 2 shows a perspective view of the desktop embodiment.

FIG. 3 depicts a hanging embodiment.

FIG. 4 shows a display according to the present invention.

FIG. 5 illustrates how other users and their viewpoint can be shown.

FIG. 6 depicts a master control loop.

FIG. 7 shows a manual control loop.

FIG. 8 depicts head tracking and range limits.

FIG. 9 illustrates eye tracking and head tracking.

FIG. 10 shows display centering within a desired range.

FIG. 11 shows robotic arm movement as head motion is extended.

FIG. 12 shows multiple users and their ability to see each other.

FIG. 13 shows manual movement of the display assembly.

FIGS. 14 and 15 depict a hollow arm embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention, which can also be called a Compact,Collaborative, Desktop, Explorer (COCODEX), is a user interfacetechnology that can provide a solution to some of the most important andlongest standing problems in Virtual Reality, Tele-immersion, 3Dvisualization, and video teleconferencing technologies. The inventionincludes an assembly of display and sensor components mounted on amechanical arm that allows the assembly to move to a wide variety oflocations around a user's head. Because the display and sensors aremobile, it is possible to keep them within constrained positions ortolerances relative to the user's face or head as the user looks around,thus making a variety of functions reliable that are not reliable inother configurations. These include auto-stereo display effects, 3Daudio without headphones, machine vision analysis of the user's face,illumination of the face, audio sensing of the voice, and so on. Thiscan be accomplished without physical contact with or obscuring of theface, so it becomes possible to accurately accomplish full duplextele-immersion or other visual communications involving the face. Theinvention is a full duplex solution for tele-immersion or visualteleconferencing that allows for varied numbers and virtual arrangementsof participants, makes demands of sensor and display technologies thatcan be met using known techniques and materials, and has a practicalfootprint for widespread deployment. The invention can be thought of asthe halfway point in a design continuum between head mounted displaysand CAVE-like room displays, while offering significant advantages thatneither extreme can offer.

As depicted in FIG. 1, the hardware of the system of an embodimentincludes two or more systems (local 102 and remote 104) connected by afull duplex communications network 106, such as the Internet. Eachsystem includes a computer 108 connected to a computer controlledrobotics arm 110. The arm 110 is a conventional robotics arm that hasmultiple degrees of freedom (with effectively 6 degrees of freedom inthe end attachment) allowing the display to tilt, swivel, move up, down,away, toward, right, left, etc. The arm also includes the conventionalfeedback systems that indicate the position and attitude of the arm sothat the direction that the display is “facing” is known. The arm 110holds a visual display 112, such as a flat panel display, to which areattached (an array of) audio speakers 114, visual sensors 116,illumination sources 118 such as LEDs, and an audio sensor 120, such asa microphone array allowing sound direction to be determined. The flatpanel display can include autostereo viewing capability by usingsuitable devices, such as a lenticular screen, through which the imagesare projected to the user. The display provides a view into the scenethat can be adjusted. The autostereo view capability allows the user tosee stereo cues in the virtual scene. The speakers and sensors arepositioned around the display so that three-dimensional (3D) effects canbe obtained and projected. For example, the visual sensors, as will bediscussed later herein, are used to sense the position of a user's headand the near field speakers can be used to present to the user a stereoaudio image that approximates a position of a participant that appearson the display 112 while at the same time not projecting the sound toofar from the physical space of the user. A handle 122 for manual controlof the positioning of the display (and the view of the object) is alsoprovided and includes one or more buttons 124 (like the buttons of aconventional mouse I/O device) or interface elements (such as rollerballs, thumb wheels, jog wheels) allowing different types of control andselection. For example, buttons and a roller ball can be used to selectand activate graphical user interface (GUI) elements that appear on thedisplay, such as a typical menu or GUI icon based desktop. These roboticarm feedback systems can provide manual resistance to movement of thehandle as controlled by the computer to allow the user to “feel” thedata through which a view or cut-plane is traveling. The components112-120 and 124 are conventional components, such as video cameras,microphones, etc and are coupled to the computer 108 throughconventional interfaces suitable to the components.

FIG. 2 depicts a perspective view of a preferred embodiment of thedesktop portion of the interface system. In this view it can be seenthat the display 112 with its attachments can be moved about above thedesktop 202 by the user with the handle 122 or the motors of therobotics arm 110.

FIG. 3 depicts an alternate embodiment where the display assembly 302hangs from an overarching gantry type device 304. In this embodiment thefreedom of movement is greater, allowing the user more views into the“space” that is being presented to the user. For example, in thisversion the screen can be turned to allow a 360-degree view in both thevertical and horizontal directions, like looking around in a room fullof people or even looking about in a theater.

The freedom of movement of the display of the present inventionessentially allows the user to move about and look about in a viewspace. As a result, the user can take a viewing frustum and move it“through” a virtual object that is being commonly displayed to theinteractive collaborating participants. FIG. 4 illustrates the display402 in such a position where a cut plane 404 through a 3D object 406 (ahead of a person) is being displayed.

Because in a situation where many individually may be involved in thecollaboration, it may be important for each viewer of a common scene tohave an understanding of at where the other viewers are looking. FIG. 5depicts a display view 502 showing a 3D object 504 being commonly viewedby another viewer 506. The other viewer 506 is being shown along withorientation of the other viewer, the cut plane 508 (or 3D object view)being viewed by the other viewer 506 and the other viewers viewingfrustum 510. The other viewer is displayed as a compound portraitureimage of the face. A compound portraiture image is an image of a userthat is constructed using the best data that can be obtained fromsensors placed in advantageous positions by the motion of the roboticarm. It is composed of a polygon mesh head deformed by facial landmarksthat are tracked by machine vision algorithms (in order to reflectfacial expression or pose), to which textures are applied. The texturesare of varying resolution, and are derived differentially from camerasin the camera array, so that the best-placed camera contributes most togiven area of texture on the head. Variably-transparent mesh objectsextend from the head so that objects that extend substantially from theface, such as large hairstyles or hats, can be rendered so as to fadeinto the surrounding environment with an ambiguous border.

FIG. 6 depicts a master flow of control within the computer system 108.A more detailed description of the flow can be found in the attachedpseudocode appendix, which can be used to for implementing the system ina preferred language such as C++. In this flow, the system determines602 whether the handle of the assembly is being touched. Thisdetermination can be made conventionally by, for example, using touchsensors on the handle. If so, the system determines 604 the view,viewing angle, frustum, etc. of the viewer and communicates such to theother systems so that they can depict to the other users the view of theviewer moving the display (see FIG. 8). In this way, the other users canbe alerted to what the viewer desires to point out, etc. The system alsomoves the assembly and adjusts the local view based on the inputs fromthe handle. If the user is not touching the control handle, the systemdetermines 606 the head position and eye view using conventional eyetracking and object motion detection procedures and moves 608 thedisplay to keep the head in the display stereo view/sound range and thesensor sensing range using conventional position prediction techniques.The display is moved by conventionally controlling the robotic arm 110based on a desired position determined by the position prediction. Asthe display is automatically moved, the system also determines 610whether the display will collide with other objects on the desktop, suchas another computer, a telephone, etc. This collision detection is alsoperformed in a conventional manner. If a collision is imminent, themotion is stopped 612. The eye tracking also determines when the user isno longer looking at items that are deemed important within the virtualworld display, such as when the user glances at an object in the localenvironment or room, such as a piece of paper laying on the desk top orat another computer display elsewhere in the room. When the systemdetermines that the user is not looking at a defined area of interestwithin the virtual world depicted in the display, head tracking andmotion of the assembly by the robotic arm stops.

FIG. 7 depicts the flow of operations of the system while the handle ofthe assembly is being touched. A more detailed description of the flowcan be found in the attached pseudocode appendix, which can be used forimplementing the system in a preferred language such as C++. If thehandle is being touched 702, the viewing frustum is determined 704 andcommunicated to the other systems. In addition, the local cut plane ishighlighted 706, along with other user interface elements, such asorientation reference guides and this information is also communicatedto the other users systems. When this communication is finished, thesystem calculates 708 the stereo views of other users along with sharedview information and projects 710 an integrated view to the viewer.

FIG. 8 depicts horizontal limits 802, 804 of head 806 motion relative tothe display/sensor array 808 for head position sensing and the roboticarm 810. As the head 806 approaches and reaches the limit 802, thesystem predicts the limit encounter and moves the arm 810 and/or swivelsthe display/sensor array 808. The position of the eyes relative to thedisplay/sensor array are used to help determine whether the display 808needed to be swiveled (or tilted). The limits are typically specified bythe optics of the stereo view system being used for image projection.The viewing geometry of a particular lenticular or other autostereoscreen being used for the display is used to set such limits.

FIG. 9 depicts the system making a predictive guess of a future orderived head position 902 of a moving head 904 using conventional eyetracking 906 and Kalman filter based prediction of future position.

FIG. 10 shows how the display assembly 1002 on the end of the roboticarm 1004 is automatically moved or swiveled 1006 to maintain the head ina desired center of the viewing/sensing range rather than by moving thearm.

FIG. 11 shows how the arm 1102 is automatically moved 1104 to provide anextended range 1006 of head motion where the user moves his head from afirst position 1108 to a second position 1110 while the system keeps theviewers head with the left 1112 and right 1114 limits. FIG. 11 alsoshows a situation where the user may be looking at a backside of a 3Dobject or scene being displayed in the first position 1108 and thefront/left side of the object in the second position 1110. With thisautomatic movement capability and the ability to view the scene within aviewing range, the users can now look at each other as well as atdifferent portions of the object.

FIG. 12 shows how several viewers in different locations can move theirheads 1202-1208 while using the system and view others in the group aswell as other parts of the common 3D scene during a collaboration. Theusers 1202-1208 have moved their heads within the head position trackinglimits while their eyes have moved to look obliquely through thedisplays. The system tracks the eye movements of the users 1202-1208 andadjusts their view into the scene accordingly. The relative spatialpositions of the users can defined with great flexibility. User's can beclose to each other or far from one another, and can be seated equallyaround a table or gathered in an audience in front of a user who isgiving a lecture.

FIG. 13 depicts a user 1302 manually moving 1304 the display to look ata particular party of the scene or at another user by grabbing a side ofthe display assembly. This particular example of motion control does notuse the handle and relies on the feedback from the position sensors inthe robotic arm and display assembly head to make adjustment to thedisplay view, etc.

The above-discussed figures show the user moving essentiallyhorizontally, the system tracking the user and moving the displayaccordingly. The system is also capable of moving the display verticallyand at angles.

The present invention also uses the conventional virtual realitycapabilities that allow a user to view a 3D scene from multiple changingperspectives and that allow other views, such as a view of another user,to be combined in the same view space.

The present invention can incorporate a merged dual-exit pupil displayas its display as depicted in FIGS. 14 and 15. There have been variedautostereo displays using multiple exit pupils, but they have eitherrequired very large footprints to handle the optics to make large exitpupils, or have demanded an artificially small amount of head motionfrom the user, so that the user can see small exit pupils. The inventionmakes smaller exit pupils 1500 usable by moving them to match the user'smoving eye positions. In an embodiment, a variation of the arm 1402/1502is required which is hollow and capable of supporting mirrors 1504 inits joints. One display 1506/1508 for each eye is placed in the base1510 and combined with a combiner 1512. These are preferably DLP or LCOSmicro-displays illuminated by LEDs or other light sources. Poweredmirrors are placed in the joints, so that the invention functions like aperiscope, incorporating the optical properties of a stereo microscope.A holographic optical element 1512 is one suitable choice for the finalpowered optical element, coincident with the plane of the sensor/displayassembly, in order to reduce weight.

The aspect of the invention of placing sensors and displays in motion toapproximately keep track of a user's head provides multiple benefits: a)Improved integration of virtual and physical tools: With the inventionit is easy to look into the 3D scene and then out again while seated,allowing users to easily divert attention between people and thingsdepicted in a virtual space and other people and things present in thephysical environment. A user can easily use conventional PC tools andimmersive virtual world tools in the same work session. b) Emulation ofother user interface designs: The invention can emulate a conventionalPC display by defining a virtual PC display at a certain position in thevirtual world. When the invention's display is moved to thecorresponding physical position it effectively acts as a physicalsimulation of a conventional PC at the same location. Similarly, theinvention can be used to emulate command/control centers, display walls,and other user interface designs. c) Improved upper-body mobility forseated users of tele-immersion services: Available eye trackingtechnologies, which are required both for facial reconstruction and forthe control of autostereo renderings, do not track eyes within the fullnormal range of human head motion during the course of a conversation inwhich a person might be looking around at multiple remote participants.By coupling eye-tracking sensors to the mobile display that is allowedto move in approximate conjunction with the eyes that are being tracked,sufficient performance is achieved to support a multi-personconversation with diverse relative positions of participants. The sameargument is generalized to all visual sensors. A single camera pointedstraight at a user is a common design in visual telecommunications, butthis design fails to meet human factors requirements. Some degree ofreconstruction of the user's head/face is needed to meet theserequirements, so that accurate lines of sight can be supported, witheach user appearing to the others at the proper perspective angle.Machine vision techniques and cameras have not performed well enough toachieve this when limited to fixed viewing positions, given normal humanranges of motion. Since with this invention cameras keep up with theface, existing cameras and machine vision algorithms can sense a user'sface well enough for perspective alteration and other tasks. d) Improvethe performance of autostereo displays: The invention enables renderingof precise points of view within autostereo displays and prevents usersfrom seeing nil, pseudoscopic, or otherwise incorrect image pairs, evenwhile supporting a full range of head motion. e) Improved independenceof physical and virtual space allocation: The physical arrangement ofdisplays in previous tele-immersion setups placed constraints on virtualparticipant arrangements. For instance, in order for a user to be ableto see remote users to the left and to the right at a virtual table,there had to be local physical displays to the left and right to supportsight lines to view those remote users. If a tele-immersive meetingusing fixed displays has more than a few participants, the displayrequirements become expensive and impractical. The invention's singlemobile display allows users to look in any direction and, thus, itforesees any number or arrangement of remote participants with only amodest and fixed requirement for local physical space. f) Improvedexploration of volumetric data: With the present invention, by equatingphysical display position and orientation with virtual viewing frustum,the user's brain is relieved from having to perform a 6D transformationthat confuses many users in typical immersive systems. This issignificant in medical and scientific applications involving selectingsectional views of volumetric data. g) Improved user interface forimplicit communication of interest and activity between users: With theinvention, users can see renderings of the locations and projectivecontents of the mobile screens other participants are viewing the worldthough, so each user can tell what the others are paying attention to.Since the invention makes it easy to perform planar selections andmanipulations in addition to point-based ones, it is easy to designvisualizations of what other participants are doing. Users see both theheads of other users, the screens they are using, and the ways thatthose screens are coupled to virtual objects that are being transformed.h) Reduced impact on the local shared physical environment: Theinvention can be desk-mounted and doesn't require low light conditions.i) Improved sound system for collaboration in a shared physicalfacility: Headphones excel at 3D audio effects, while speakers, thoughconvenient, don't produce these effects well when placed at conventionaldistances, despite a great deal of effort by many labs to get them to doso. Speakers can also be loud when placed conventionally and this candisturb others in a work environment. By coupling near-field speakersapproximately to head position, the invention provides 3D sound at lowvolumes without head contact and without demanding any time to get intoor out of the interface. A similar issue exists with microphones. Amobile microphone or microphone array will pick up the voice moreconsistently. j) Improved integration of audio, haptic, and visual userinterface modalities: The invention can be used for planar explorationof a scalar or vector volumetric field- or even one with curl. The userinterface of exploration using any of the three above sensory modalitiesis identical (moving the display), and this tight integration will makeit easier to train and collaborate with users who have certaindisabilities. That is to say, a blind user and a deaf user could eachexplore a virtual object in similar ways, and thus collaborate moreeffectively. For the blind user, a haptic display, as described indetail in the pseudocode below, will be available, in addition to anaudio display. For instance, the center of density, as calculated toprovide haptic feedback of the location of a tumor in the pseudocodebelow, could also be used as the source of a virtual sound source usingconventional 3D sound rendering techniques.

As can be seen from the above discussion and the attached drawings, thepresent invention solves a number of problems related to positions ofsensors and displays. The invention provides autostereo withoutconstraining user position unacceptably, provides headphone-like 3Daudio performance without headphones, performs visual facial sensingwithout constraining user position unacceptably, provides consistentillumination of the user's face, isolates the user's voice withoutconstraining user position unacceptably, provides a compact desktopimplementation, facilitates instant-in-and-out, easy overall workflowwhen used in conjunction with other user interfaces, easily depicts whatother users are paying attention to and doing, and provides 6 degrees offreedom of the physical display and the virtual viewing frustum, whichare equivalent, making it easier for users to understand six degree offreedom navigation.

Other techniques can be used for head position and orientation sensing.For example, a 3D magnetic field based sensor system, such as Polhemussensor and sensor system available from Polhemus, Colchester, Vt., canbe worn on the user's head. These sensors can also be used to warn theuser to manually move the display with the attached sensors when theuser's head position is reaching a limit.

The invention arm can be mounted on a floor-standing pedestal, or arolling such pedestal. The arm can be ceiling-mounted. The arm can bemounted on a powered mobile base, so that the base moves on a table orother surface in addition to the other motions described above. A mobilefloor-mounted base can be incorporated to make the invention functionalfor a walking user.

The display/sensor assembly can be hand-supported, if position andorientation are sensed using sensors such as those described above whichdo not require a rigid mechanical linkage. The display/sensor assemblycan be hand-supported and wireless, using protocols, such as Bluetooth,to connect all components with computation resources.

The arm can be mechanically supported, but manually moved.

The invention display can be a transparent or semi-transparent surfacethat can present to the user superimposed projected images over thephysical scene which is visible beyond the display surface. In thiscase, the invention incorporates the functionality of “AugmentedReality” displays (which are well known). When an “Augmented Reality”type display is chosen, the arm can be mounted on the inside surface ofa vehicle. This can be done to provide simulated presence of otherpassengers in the vehicle, such as flight instructors (in the case of anaircraft). Another example of this variation is a set of commuter trainswith invention systems present in each train, so that passengers ondifferent trains could simulate being on the same train at once in orderto have a meeting while commuting.

The arm can be supported by the human body through a mounting systemthat attaches to a helmet, or directly to the human head, shoulders,and/or waist. When attached to the head, the invention resembles ahead-mounted display, but is unlike other head-mounted displays in thata) there is sufficient clearance from the face for facial sensing tosupport tele-immersion, and b) small amounts of motion of the displayrelative to the head are acceptable because the techniques describedthroughout this patent compensate for them.

The screen and other components can be mounted on the mechanical armusing clips or clamps or other easily disengaged fasteners. Thisfacilitates rapid changing of the choice of components present in theinvention. For instance, a user can switch between autostereo and higherresolution non-stereo displays.

The invention can be constructed as a product that includes the arm andthe software described in the pseudocode below, with each user addingsensing and display components according to individual preferences.

The invention can incorporate a conventional computer display, mountedon the reverse side of the autostereo display, facing in the oppositedirection. When the user is performing conventional computer tasks, thearm swivels the display/sensor assembly so that the conventional displayis facing the user, and when the user wishes to perform tasks suitablefor the invention, the assembly is turned so that the autostereo displayis facing the user. The turning action (which switches from anautostereo to a conventional display) can be triggered when the usermoves the assembly so that it is coincident with the placement of asimulated conventional computer display in the virtual space.

The invention can incorporate a front or rear projection screen as itsdisplay, where the display surface is in motion, but the light source iseither stationary or in motion to a lesser degree. In this case theprojected image must be directed and distorted to correct for thechanging relative placements of the light source and the projectionsurface, which can be accomplished by various established means, such asmoving mirror and lens systems and computer graphic techniques forsimulated optical anti-distortion.

The invention can incorporate a screen element which, rather than beingflat, as described above, is concave, in order to provide the user withan effectively wider-angle display.

A subset of the components described as being mounted on the arm caninstead be mounted separately on a stationary or less mobile platform.For instance, a stationary light source can be substituted for themobile light sources preferred in this description, or a stationaryaudio sensing or display system can be substituted.

The invention can incorporate only a subset of the displays or sensorsdescribed in the preferred embodiment. For instance, a silent versionmight incorporate only the visual components, and none of the audioones.

A barrier can be incorporated which surrounds the space to the rear ofall the positions the arm and the display/sensor assembly can attain,with sufficient clearance for operation, but which is open in front togive the user access to the device. This is an alternative orenhancement to relying on collision detection and prevention subsystemsto prevent collisions between the arm or assembly and people or objectsin an environment. An embodiment of this barrier is an approximatesection of a sphere in shape, transparent and composed of a lightweightmaterial like plastic. The barrier can be made in several sections thatcan be attached or detached to facilitate transport.

The mobile portions of the invention can be made largely of low-weight,soft materials. For instance the display screen can be a softrear-projection surface, such as plastic, or a flexible (such as OLED)display. Soft audio speakers are available which are made of piezo andother materials. While soft versions of the sensor components (such ascameras, microphones, and position/orientation sensors) are notavailable at this time, versions of these components are available whichare low weight and small. A version of the invention in which themajority of the mass of the components in motion is comprised of soft,lightweight materials will have reduced requirements for collisionavoidance.

The invention can incorporate additional optical components to provideaccommodation relief for certain autostereo displays. That is to say,the distance at which the user's eyes must focus to resolve the stereoimages presented in the display can be changed by incorporating theseoptical elements. A set of lenses, Fresnel lenses, holographic opticalcomponents, or other optical devices can be mechanically connected tothe invention and positioned appropriately between the user's eyes andthe display. It should be pointed out that these optical componentstypically only function under narrow positioning tolerances, so the sametechnique that is used to make other invention components function, ofhaving the components move to track the head's location, makes itpossible to incorporate such optical elements.

The accommodation relief optical elements described in the previousparagraph can be mounted on a separate arm or a subordinate arm. This isdesirable if the positioning tolerances of the optical components aretighter than the display. The same control software

1. A system, comprising: multiple input/output systems coupled togetherto provide a view of a common scene from perspectives of each of thesystems, each system comprising: a display/sensor assembly presentingthe view to a viewer and sensing a user position and user viewpoint; arobotic arm coupled to the assembly and providing display position andorientation information; a computer determining the view responsive tothe user position and viewpoint, producing a display responsive to theposition and viewpoint, comparing the user position to position rangelimits and producing robot motion control information to keep the userposition within the range limits, the robotic arm moving and orientingthe assembly responsive to the motion control information.
 2. A systemas recited in claim 1, wherein each assembly includes a video sensorarray capturing a multiple view image of a first user and the systemdisplays the image of the first user via the assembly of a second user.3. A system as recited in claim 2, wherein the image displayed via theassembly of the second user comprises a compound portraiture of the faceof the first user.
 4. A system as recited in claim 1, wherein eachassembly includes a sound sensor array and a speaker array and saidsystem captures a sound of a first user via the sound sensor array andprojects the sound of the first user to a second user via the speakerarray.
 5. A system as recited in claim 1, wherein the assembly can bemoved by a hand of a user to a manual position and the computer adjuststhe view of the common scene responsive to the manual position.
 6. Asystem as recited in claim 1, wherein the view of the common sceneincludes a cut plane view of objects in the scene.
 7. A system asrecited in claim 1, wherein the view of the common scene comprises anautostereo three-dimensional view.
 8. A system as recited in claim 1,further comprising a full duplex communication system connecting theinput/output systems.
 9. A system as recited in claim 1, wherein the armis hollow and the view is projected through the arm.
 10. An input/outputinterface, comprising: a display providing a three dimensional view of ascene; speakers attached to the display and providing a stereo sound;tracking sensors attached to the display and tracking viewer head motionand eye position; sound sensors attached to the display and detectingsound direction; a handle attached to the display and allowing a user tocontrol position and orientation of the display; and an I/O controlinterface attached to the handle.
 11. A process, comprising: sensing aposition of a user relative to a virtual scene; and adjusting a viewinto the virtual scene responsive to the position using a computer. 12.A system, comprising: a communication system; first and second displayand capture systems each locally capturing images and sound andtransmitting the locally captured images and sound over thecommunication system, and receiving remotely captured images and soundand displaying/playing the remotely captured images and sound to aviewer and where each display and capture system comprises: a desk toprobotic movable arm having three degrees of freedom; a movable displayconnected to an end of the movable arm, having three degrees of freedomand movable independently of the arm and displaying the remotelycaptured images and a common stereo image; a stereo/autostereo imageprojection system associated with the display for projecting a stereoimage of the captured images to a viewer of the display and having apreferred viewing angle; near field speakers producing stereo sound fromthe remotely captured sound; video sensors including cameras mounted onthe display and for capturing a stereo image of a head of a viewerviewing the display; light sources in association with the videosensors; sound sensors including microphones mounted on the display forcapturing stereo sound from the head of the viewer viewing the display;a touch sensitive handle attached to the display/arm allowing a user tomove the display and providing direction and movement amount outputs;and a computer system, communicating with the communication system;processing the locally captured stereo image using Kalman filter todetermine a head position and head orientation of the head of theviewer; processing the locally captured stereo image to determine an eyeposition of the viewer; adjusting a position of the movable arm and themovable display, when the handle is not being touched, to maintain thehead of the viewer within the viewing angle and responsive to anenvironmental constraint map indicating objects within the movementrange of the display and arm; adjusting a position of the movable armand the movable display responsive to the direction and movement amountoutputs when the handle is being touched; transmitting the locallycaptured images and sound, the head position and orientation, the eyeposition and the display/arm position through the communication system;processing remotely captured images for display through the stereo imageprojection system by the movable display; processing remotely capturedsound and providing the stereo sound to the speakers; processing theremotely captured images to determine a viewing frustum of a remoteviewer responsive to the remotely determined head position andorientation, eye position and the remote display/arm position anddisplaying the viewing frustum on the display associated with a view ofthe remote viewer showing an orientation of the remote viewer;maintaining a 3D object in a common world coordinate system being viewedby the first and second systems; determining a cut plane view of the 3Dobject on the display responsive to a position of the display withrespect to the common world coordinate system, displaying a view of the3D object on the display; displaying the frustum of the remote viewerrelative to the 3D object on the display; and displaying arepresentation of the cut plane view of the remote viewer on thedisplay.
 13. A system, comprising: an autostereo display; a mechanicalarm coupled to the display and providing display position andorientation information; and a computer determining autostereo viewsresponsive to the display position and viewpoint.
 14. A system,comprising: a display/sensor assembly presenting a view to a viewer andsensing a user position and user viewpoint; a robotic arm coupled to theassembly and providing display position and orientation information; anda computer determining the view responsive to the user position andviewpoint, producing a display responsive to the position and viewpoint,comparing the user position to position range limits of sensor anddisplay components and producing robot motion control information tokeep the user position within the range limits, the robotic arm movingand orienting the assembly responsive to the motion control information.15. A system, comprising: multiple input/output systems coupled togetherto provide a view of a common scene from perspectives of each of thesystems, each system comprising: a display/sensor assembly presentingthe view to a viewer and sensing a user; a mechanical arm coupled to theassembly and providing display position and orientation information; anda computer determining the view responsive to the display position andorientation.